Given the expression B= a(c+y), we are told to solve for y.
We can do that by making y the subject of the formula;
To do that kindly follow the steps
open the parenthesis at the right hand side of the equation using the distributive law;
B = ac+ay
Next is to subtract ac from both sides of the equation
B - ac = ac+ay-ac
B-ac = ay
Rewrite the expression
ay = B-ac
Lastly, divide both sides of the resuting equation by a
ay/a = (B-ac)/a